1. Field of the Invention
This invention relates generally to physical therapy devices for rehabilitation of patients with leg and spinal cord injuries or other gait pathologies. More particularly, this invention relates to physical therapy devices for use in conjunction with a treadmill for assisting in the movement of the legs of a patient.
2. Description of the Related Art
Patients with impaired walking ability or paralysis due to spinal cord or brain injury, stroke, or other neurological or orthopedic condition are often prescribed physical therapy for rehabilitation and maintenance of muscle strength. Traditionally, walking therapy is performed on a motorized treadmill and the patient is assisted, in the case of impairment to both legs, by three physical therapists. The patient is suspended above the treadmill in a torso harness attached to a fixed or limited movement point. Two of the therapists, one for each leg, manually advance the patient's legs to impart a walking stride. The treadmill drags the patient's foot through the rearward portion of a walking swing motion. At the completion of the rearward movement, each therapist lifts one of the patient's feet from the treadmill and swings the foot and leg forward to place it on the belt toward the front of the treadmill to begin the walking cycle again. A third therapist is generally required to assist the patient in maintaining a generally constant position over the center of the treadmill by counteracting the rearward force of the treadmill.
While effective, manually assisted walking therapy does have some drawbacks. A significant disadvantage is the physical exertion required on the part of the therapists. Assisting with patient leg movement is physically taxing and can generally only be performed for a few minutes at a time. Further, manual leg manipulation can cause detrimental physical effects in the therapists, notably repetitive motion stress disorders from the constant movement of the patient's legs and back strain due to the low, crouched position required to manipulate the foot and lower leg of a patient.
In recent years, the introduction of robotic-assisted walking therapy has reduced the physical exertion required of the physical therapist to conduct the walking therapy. One exemplary robotic assist device is the LOKOMAT® Robotic Gait Orthosis (Hocoma AG-Volketswil, Switzerland). As with regular therapy, a patient with significant paralysis is generally suspended above a motorized treadmill in a harness in a standing orientation with the patient's feet in contact with the treadmill. Alternatively a patient with some weight bearing capacity may be minimally assisted with a weight harness or support himself, perhaps with the assistance of rails. A robotic exoskeleton is then fastened to the legs of the patient, which when activated causes the patient's legs to move in a regular walking motion as the motorized treadmill moves underneath the feet of the patient. The robotic assist thus replaces two of the three physical therapists that previously manually manipulated the patient's legs. The device thus reduces labor costs in the rehabilitation process as well as fatigue and potentially repetitive stress or back injuries suffered by the therapists. At least one physical therapist is still required to operate the device and monitor the treatment.
While the robotic assist devices offers several advantages over traditional manual walking therapy, there are several disadvantages. The most significant disadvantage is the high cost of the robotic assist device and therefore limited patient access and availability. In fact, very few rehabilitation treatment facilities today are equipped with such devices. Thus, many patients who could benefit from such treatment do not have access. Additionally, there has been some concern with limitations of the efficacy of the robotic assist devices. While a robotic assist device does provide some muscle exercise for patients, it can also encourage patients to minimize their own exertion and efforts because the robotic assist will perform all the movement for the patient. Further, the robotic assist devices are very controlled in the movements they impart to the legs and thus lack the benefit that more natural leg movements can impart.
The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded subject matter by which the scope of the invention is to be bound.